* {
  margin: 0;
  padding: 0;
  touch-action: none; //任何触摸事件都不会产生默认行为，但是 touch 事件照样触发。来源：https://blog.csdn.net/lijingshan34/article/details/88350456
  font-family: "Helvetica Neue",Helvetica,"PingFang SC","Hiragino Sans GB","Microsoft YaHei","微软雅黑",Arial,sans-serif;
}
li {
  list-style-type:none;
}
:focus {
  outline: -webkit-focus-ring-color none 1px;
}